GDD: Daily growing degree days (GDD)

In VEZY/DynACof: A Process-Based Model to Study Growth, Yield and Ecosystem Services of Coffee Agroforestry Systems

Description

Compute the physiological degree days at daily time-step using the maximum and minimum daily temperature (and optionally using the average daily temperature, not recommended).

Usage

GDD(Tmax = NULL, Tmin = NULL, MinTT = 5, Round = T, Tmean = NULL)

Arguments

Tmax	Maximum daily temperature (Celsius degree)
Tmin	Minimum daily temperature (Celsius degree)
MinTT	Minimum temperature threshold, also called base temperature (Celsius degree), default to 5.
Round	Boolean. /!\ Important: round the result to 2 decimal, with default to TRUE.
Tmean	Optional. Average daily temperature (Celsius degree). Only needed if Tmax and Tmin are missing.

Details

Please keep in mind that this function gives an approximation of the degree days. GDD are usually computed as the integral of hourly (or less) values. The round argument is provided for convenience, as growing temperatures with less than 3 digits are likely to be within the measurement error, and will probably have no visible effect on plant phenology. Caution, use Tmean only if Tmax and Tmin are not available because it tends to give less powerful estimation.

Value

GDD	Growing degree days (Celsius degree)

Examples

# Growing degree days over 10 days :
# Set the seed :
set.seed(1)
GDD(Tmax = rnorm(n = 10, mean = 30, sd = 1),
    Tmin = rnorm(n = 10, mean = 10, sd = 1),
    MinTT = 10)

VEZY/DynACof documentation built on Feb. 3, 2021, 8:52 p.m.